2007 GMC Yukon XL 5.3l. Bad rod bearing. New engine?

fdalesfinest

On friday coming home from work my 2007 Yukon xl truck was driving great and then suddenly I hear this ridiculously loud clanking noise that gets worse upon acceleration. No warning lights come one so I limp home the final two miles.

I check the oil and it shows I am a 1/2 quart from full. I have had excessive oil consumption since about 40k and it has 129k now. My dealership said 1 qt per thousand miles is normal and they wouldn't do anything about it. I spoke to my normal mechanic and he said its ridiculous but that is what GM considers normal.

I go on google and put in a search for what I heard while the truck was running and it seems I may have a bad rod bearing. With what I read it says I would either need a engine rebuild or a new engine. Is this likely?! Part of the reason I bought this truck was because it isn't unusual to have the engine last 250-300k.

Then my next question is I found a local new 2013 5.3 for a GMC Sierra with 8 miles on it for $2500 minus the injectors, valve covers, TB and pan. Will this bolt into my 2007 and if so will I be able to swap these part from my current truck?

Thanks in advance!

Mr_Shiftright

It's hard to say what's going on here, from this distance. Certainly being just 1/2 quart down on oil is not going to cause a rod bearing failure.

As for the noise you hear---has a qualified mechanic verified that it's a rod bearing? This is a very sharp rhythmic knock, like a hammer inside the engine, and generally not heard at slow idle--only when you hit the gas.

You may have other, less drastic problems, like timing chain noise, which can put up quite a racket.

IF in fact you have a bad rod bearing, then your crankshaft is ruined for sure and you will need at least a partial rebuild.

The truck is definitely worth fixing of course.

I'm not sure the 2013 engine will work out for you. The price is great but someone has to figure out all the electronics---you may need the 2013's "brain" as well, and there are bound to be differences in sensors, connectors, etc. You may end up with a very expensive install.

So to summarize---first, determine the exact problem. If it's the engine, I'd investigate ordering a new "crate" engine from GMC, or a "short block". At least then you'll have a warranty.

fdalesfinest

I got a call from my mechanic today and he said there is a lifter tap. He wants to flush and change the oil and see if that takes care of the sound if it doesn't then it is more serious. He will be doing this tomorrow.

fdalesfinest

Mr_Shiftright said:

As for the noise you hear---has a qualified mechanic verified that it's a rod bearing? This is a very sharp rhythmic knock, like a hammer inside the engine, and generally not heard at slow idle--only when you hit the gas.

This is exactly the way the noise was....As I accelerated and the rpm's increased the louder the banging got.

fdalesfinest

It sounds like I dodged a bullet. I got a call from my mechanic this morning and he said I could pick my truck up. They did an oil change and an engine flush and it cleared up the issue!

I was hoping for the best but expecting the worst based upon what I had read on this and other forums regarding the AFM 53.l engine. I thought I would be replacing the motor.